Cured reaction product of unsaturated acetal, polyhydroxyalcohol and cellulose and process for preparing same



United States Patent CURED REACTION PRODUCT OF UNSATU- RATED ACETAL, POLYHYDROXYALCOHOL AND CELLULOSE AND PROCESS FOR PRE- PARING SAlVlE Donald E. Hudgin, Summit, N.J., assignor to Celanese Iorporanon of America, New York, N.Y., a corporatron of Delaware No Drawing. Filed Apr. 9, 1957, Ser. No. 651,573

14 Claims. (Cl. 2'6017.4)

This application relates to resins produced from unsaturated polyacetals and polyhydroxy alcohols and more particularly to resins produced with cellulose as a polyhydroxy alcohol.

It is known that hard, tough resinous polymers may be produced by reacting an unsaturated polyacetal, such as diallylidene pentaerythn'tol with certain polyhydroxy alcohols. The suitable polyhydroxy alcohols have been found to be those with at least two but not more than six hydroxy groups having at least two hydroxy groups separated from one another by a carbon bridge of at least three carbon atoms. Among the specific polyhydroxy alcohols disclosed are the hexa-hydroxy sugar alcohols such as mannitol, sorbitol and dulcitol; and trimethylol propane, trimethylol ethane 2,3,5,6-tetramethylol-1,4-hydroquinone dimethyl ether and 2,4-hydroXy-3 hydroxmethyl pentane.

It has been found that polyhydroxy alcohols containing more than six hydroxy groups are generally not suitable. For example, sucrose and amylose do not react with diallylidene pentaerythritol under-conditions effective for the reaction of the above-mentioned polyhydroxy alcohols and cellulose reacts with diallylidene pent-acrythritol to produce a white, brittle and fragile product.

In accordance with this invention, it has been found that, while cellulose, as the sole polyhydroxy alcohol produces the aforesaid brittle and fragile product, it may be substiuted for a portion of the polyhydroxy alcohol normally used to produce a tough, useful resin.

In the preferred embodiment of this invention, the unsaturated diacetal is combined with a less than stoichiometric amount of polyhydroxy alcohol and a suitable catalyst and is precured at a temperature above the fusion point of the mixture but below about 100 C. The precured resin is then combined with cellulose and the curing is continued, under pressure, if desired, for a period between about 12 and 24 hours at a temperature between about 70 and 120 C.

The diacetals which may be used in accordance with this invention are those prepared from pentaerythritol and from anhydroenneaheptitol and an m,fl-ethylenioally unsaturated aliphatic aldehyde preferably a straight chain a,B-ethylenically unsaturated aldehyde having not more than four carbon atoms. Pentaerythritol forms diacetals with acrolein and crotonaldehyde, for example, in the presence of a small amount of acid, such as phosphoric acid, as catalyst.

, droenneaheptitol may be found in United States applicati'on Serial Number 651,572, filed by Donald E. Hudgin concurrently herewith.

The polyhydroxy alcohols, used in addition to cellulose, in accordance with this invention are those having at least two but no more than six hydroxy groups and having at least two hydroxy groups separated from each other by a carbon bridge of at least three carbon atoms. Among the specific polyhydroxy alcohols which may be used are trimethylol propane; trimethylol ethane; 2,3,5,6-' trimethylol 1,4 hydroquinone dirnethylether; 2,4-dihydroxy 3 hydroxymethyl pentane; glycerine; 1,2,6-hex :anet-riol; 1,2,4-butanetriol; methyl glucoside; and dextrose. Among the most useful of the polyhydroxy alcohols are the hexa-hydroxy sugar alcohols such as mannitol, sorbitol and dulcitol. Of these sorbitol is preferred because of its greater solubility in the unsaturated di acetal and 'because of the superior physical properties of the resins produced. 7

The aforementioned polyhydroxy alcohols are com bined in less than stoichiornetric amounts with the unsaturated polyacetals in accordance with this invention in order to permit reaction with the hydroxy groups of the cellulose to take place. Instead of an equivalent amount of polyhydroxy alcohols and unsaturated diacetals, based upon hydroxy groups per double bond, a

.lesser amount, from about 0.4 to about 0.9 equivalent, is

used. It is preferred that an amount between about 0.5 to about 0.7 equivalent be used.

Any of the known catalysts of acidic nature known to be effective for the production of resins from unsaturated diacetals and polyhydroxy alcohols may be used as a catalyst in accordance With this invention. Among the classes of catalysts which may be used are the boron fluoride complexes, such as boron fluoride hydrate, boron fluoride etherate and boron fluoride acetic acid complexes; organic sulfonic acids, such as p-toluene sulfonic acid, d-camphor sulfonic acid, 2'-chlo'rcymol sulfonic acid, ethane sulfonic acid and m benzene sulfonic acid; and tin chloride complexes such as tin chloride-hydrochloric acid hexahydrate. The amount of catalystadded depends on the activity of thecatalyst and upon the rapidity of curing desired. With a boron fluoride complex as little as a few thousandths of one percent by weight may be used. With other catalysts the amount may be as high as l or 2 percent by weight. Generally, it is preferred to use amounts between about 0.2 and about 1.0% byweight. p

After the unsaturated diacetal, the polyhydroxy alco hol and the catalyst are combined, the admixture is fused and permitted to precure for a period between about 0.5 to about 1.0 hour at a temperature above the fusion point but below about C. The precured mixture is then combined with cellulose. v

The cellulose used in accordance with this invention may be in any convenient form such as wood flour, shredded rags, shredded paper, cotton flock, fiber cotton, wood pulp, cellulose mats, canvas or paper. From about 0.3 to about 2.0 equivalents of cellulose per equivalent of original unsaturated diacetal, based upon hydroxy groups per double bond are used. The excess cellulose, if any, acts as a filler in the resin. v

The cellulose, if finely divided is added to the precured resin. Otherwise the precured resin is impregnated into the cellulose, as for example in the case of cellulose mats.

The curing is then continued at a temperature between about 80 C. and about C. for a period between The temperature may vary within the above range at various stages in the cure and the resin may be subjected to pressure, if desired, during at least a portion of the curing process. The curing ca'talyst in the original admixture remains effective for fby' Letters Patent is:

final cure, although ifdesired, additional catalystmay be added.

V EXAMPLEI 'Diallylidene pentaerythritol (159 parts by weight) sorbitol (27 parts by weight) and ethane sulfonic acid' (1 part by weight) were stirred'together in an open flask at 90..C. The mixture became homogeneous after about 45 minutes and was then poured onto three /s" thick sheets of cellulose mat (about 8 sq. in. total for each 100 'g. of mixture). 7 The resin'saturated sheets were then placedin an oven at 80 C. for 4 hours. The laminate was then removed and placed in an oven at 90 C. for 18 hours. A hard strong board was thus produced having properties as listed in the table below. a

. EXAMPLE II p 1 Diallylid'ene pentaerythritol (63.6 parts by weight), sorbitol (l0.8 parts by Weight) and ethane sulfonic acid 10.65 part 'by weight) were stirred together at 90 C. until "the mixture'b'ecame homogeneous. It was then poured in amold and cured at 80 C. for 18 hours. The lanel, thus formed, had the physical properties as indicated inthe table below.

7 Table It may therefore be seen that an improved material results where cellulose is usedin combination with sorbitol. 'While the invention has been described in its preferred aspect, it is to' be understood that other procedures may also be used. For example, it is not essential to precure the resin in the absence of cellulose. If desired, cellulose may 'be added to'the initial mixture and all ingredients may be cured together; V It is to be'understood that the. foregoing detailed description'is merely given by way of illustration and that many variations may be made therein without departing from the spirit of my invention. p

Having described my inventiomwhat I desire to secure I 1. Process for the'production of a resin which compris es combining an a,B.-ethylenically unsaturated diflacetal of an u,;8-ethylenically unsaturated aldehyde and a vpolyhy clroxy compound selected from the group con- 7 'sisting of pentaerythritol and anhydroenneaheptitol with an amount, insufiicient to curethe ,acetal completely, of

a .polyhydroxy alcohol containing at least two, but not more .than six hydroxy groups, at least two hydroxy.

presence of an acidic catalyst at'a temperature between groupsfbeing separated fromeach other by a carbon bridge of at least three carbon atoms, procuring the thus obtained mixture by maintaining it in the presence of an acidic catalyst at atemperature above its fusion point and below about 100 C. for aperiod between 0.5 and 1.0 hour, thereafter combining the precured mixture with cellulose, and curing the thus obtained admixture by maintaining it in the presence of an acidic catalyst at a temperature between about80 C. and 120i C. for a pe friod between about '12 and 24 hours. 7 2. Process for the production of a'rcsin which com- "prises combining an unsaturated diac etal prepared from gpentaer ythritol and a straight-chain a,,8-ethylenically un-' Lsaturated aldehydehaving'no't more" than four carbon atoms with an amount, insufficient to cure the'acetal com- -;plet ely,'ofiacpolyhydroxyialcohol containing at least two,

1;- butnot-moi-e :thansix :hydroxy groups, at least two hy-' droxy groups being separated from each other by a carbon bridge of at least three carbon atoms, .precuring the thus obtained mixture by maintaining it in the presence of an acidic catalyst at a temperature above its fusion point and below about 100 C. for a period between 0.5 and 1.0 hour, thereafter combining itli'e procured mixture with cellulose, and curing .the thus obtainededrnixture by maintaining it'in the presence of an acidic catalyst "at a emperature between about C. and 120 C. for a period between about 12 and '24 hours. 7 V a 3. Process for the production of a resinwhich comprises combining an unsaturated diacetal prepared from pentaerythritol and straight chain 'a,/3-ethylen ical ly unsaturated aldehyde having not more than four carbon atoms, with a ,polyhydroxy alcohol containing "at :least two, but not more th-an six "hydroxy groups, at least two hydroxy groups being separated from each other by a carbon bridge of at least three carbon atoms, precuring the thus obtained mixture by maintaining it in the presence of an'acidic catalyst at a temperature above its fusion point and below about C. for a period between 0.5 and 1.0 hour, thereafter combining the precured mixture with cellulose, the reactants being present in the proportions of from about 0.4 to about 0.9 equivalent of'polyhydroxy alcohol per equivalent of diacetal and from about 0.3 to about 2.0 equivalents of cellulose per equivalent of diacetal, in each case based upon hydroxy groups per double bond, and curing the thusobtained admixture'by maintaining it in the presence of an acidic catalyst at a temperature between about 80 C. and C. for a period between about 12 and 24 hours.

4; The process of claim 3 wherein the cellulose is in the form of wood flour. 7

5. The process of claim 3 wherein the celluloseis in the form of cellulose mats.

6. Process for the production of a resin which co prises combining an unsaturated diacetal prepared from pentaerythritol and an a uethylenically unsaturated aldehyde having not more than four carbon atoms with a -hexahydroxy sugar alcohol in the proportion of from about 0.4 to about 0.9 equivalcnt'of hexahydroxy alcohol per equivalent of diacetal based upon hydroxy groups per double bond, precuring the thus obtained admixture by maintainingit in the presence of an acidic catalyst at a temperature above its fusion point and below about 100 C; for a period between 0.5 and 1.0 hour thereafter combining the precuredmixture with from about 03 to about 2.0 equivalents of cellulose per equivalent of diacetal'basedu-pon hydroxy groups per double bond,

and'curing the final admixture by maintaining it in the about 80 C. and. 120 C. "for a period between about 12 and 24 hours.

7. Process for the production of a resin which comprisescoinbining diallylidene' pentaerythritol with sorbitol in the proportion of from about 0.4 to about 0.9 equivalent of sorbitol per equivalent of 'diallylidene pentaerythritol based. upon hydroxy groups per double bond, precuring the thus obtained admixture by maintaining it in the presence of an acidic catalyst at a temperature above its fusion point and below about 100 C.

for a period between 0.5 and 1.0 hour, thereafter com bining the precuredl mixture with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of diallylidene pentaerythritol, based upon hydroxy groups per-double bond, and curing the fi-nal'admixture by maintaining it in the presence of an acidic catalyst at a term j perature between about 80 C. and 120 C. fora period between about 12 and 24 hours.

lylidene pentaerythr itol based upon hydroxy groups .per

double bond, procuring the thus obtained adrnhitureby maintaining it in the presence of an acidic catalyst at a temperature above its fusion point and below about 100 C. for a period between 0.5 and 1 hour, thereafter combining the precured mixture with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of dicrotonallylidene pentaerythritol based upon hydroxy groups per double bond, and curing the final admixture by maintaining it in the presence of an acidic catalyst at a temperature between about 80 C. and 120 C. for a period between about 12 and 24 hours.

9. A cured reaction product of an a,B-ethylenically unsaturated diacetal of an u,;3-ethylenically unsaturated aldehyde and a polyhydroxy compound selected from the group consisting of pentaerythritol and anhydroenneaheptitol with an amount, insufficient to cure the acetal completely, of a polyhydroxy alcohol containing at least two, but not more than six hydroxy groups, at least two hydroxy groups being separated from each other by a carbon bridge of at least three carbon atoms, and with cellulose.

10. A cured reaction product of an unsaturated diacetal prepared from pentaerythritol and a straight chain u,;3-ethylenically unsaturated aldehyde having not more than four carbon atoms, with an amount, insufiicient to cure the acetal completely, of a polyhydroxyl alcohol containing at least two, but not more than six hydroxy groups, at least two hydroxy groups being separated from each other by a carbon bridge of at least three carbon atoms, and with cellulose.

11. A cured reaction product of an unsaturated diacetal prepared from pentaerythritol and an a,;8-ethylenically unsaturated aldehyde having not more than four carbon atoms, with from about 0.4 to about 0.9 equivalent per equivalent of diacetal, based upon hydroxy groups per double bond, of a polyhydroxy alcohol containing at least two but not more than six hydroxy groups, at least two hydroxy groups being separated from each other by a carbon bridgeof at least three 6 carbon atoms, and with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of unsaturated diacetal, based upon hydroxy groups per double bond.

12. A cured reaction product of an unsaturated diacetal prepared from pentaerythritol and an u,fi-ethylenically unsaturated aldehyde having not more than four carbon atoms with from about 0.4 to about 0.9 equivalent of a hexahydroxy sugar alcohol per equivalent of diacetal, based upon hydroxy groups per double bond, and with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of unsaturated diacetal, based upon bydroxy groups per double bond.

13. A cured reaction product of diallylidene pentaerythritol with from about 0.4 to about 0.9 equivalent of sorbitol per equivalent of diallylidene pentaerythritol, based upon hydroxy groups per double bond, and with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of unsaturated diacetal, based upon hydroxy groups per double bond.

14. A cured reaction product of dicrotonallylidene pentaerythritol with from about 0.4 to about 0.9 equivalent of sorbitol per equivalent of dicrotonallylidene pentaerythritol, based upon hydroxy groups per double bond, and with from about 0.3 to about 2.0 equivalents of cellulose per equivalent of unsaturated diacetal, based upon hydroxy groups per double bond.

References Cited in the file of this patent UNITED STATES PATENTS 2,467,430 Izard Apr. 19, 1949 2,527,853 Roach et a1. Oct. 31, 1950 2,569,932 Izard Oct. 2, 1951 2,687,407 Orth Aug. 24, 1954 2,785,996 Kress Mar. 19, 1957 FOREIGN PATENTS 838, 27 Germany May 12, 1952, 

1. PROCESS FOR THE PRODUCTION OF A RESIN WHICH COMPRISES COMBINING AN A,B-ETHYLENICALLY UNSATURATED DIACETAL OF AN A,B-ETHYLENICALLY UNSATURATED ALDEHYDE AND A POLYHYDROXY COMPOUND SELECTED FROM THE GROUP CONSISTING OF PENTAERYTHRITOL AND ANHYDROENNEAHEPTITOL WITH AN AMOUNT, INSUFFICIENT TO CURE THE ACETAL COMPLETELY, OF A POLYHYDROXY ALCOHOL CONTAINING AT LEAST TWO, BUT NOT MORE THAN SIX HYDROXY GROUPS, AT LEAST TWO HYDROXY GROUPS BEING SEPARATED FROM EACH OTHER BY A CARBON BRIDGE OF AT LEAST THREE CARBON ATOMS, PRECURING THE THUS OBTAINED MIXTURE BY MAINTAINING IT IN THE PRESENCE OF AN ACIDIC CATALYST AT A TEMPERATURE ABOVE ITS FUSION POINT AND BELOW ABOUT 100*C. FOR A PERIOD BETWEEN 0.5 AND 1.0 HOUR, THEREAFTER COMBINING THE PRECURED MIXTURE WITH CELLULOSE, AND CURING THE THUS OBTAINED ADMIXTURE BY MAINTAINING IT IN THE PRESENCE OF AN ACIDIC CATALYST AT A TEMPERATURE BETWEEN ABOUT 80*C. AND 120*C. FOR A PERIOD BETWEEN ABOUT 12 AND 24 HOURS. 